Maintain version id across model disposing

src/vs/editor/common/model/textModel.ts

@@ -705,6 +705,10 @@ export class TextModel extends Disposable implements model.ITextModel {
 		this._alternativeVersionId = this._versionId;
 	}
 
+	public _overwriteVersionId(versionId: number): void {
+		this._versionId = versionId;
+	}
+
 	public _overwriteAlternativeVersionId(newAlternativeVersionId: number): void {
 		this._alternativeVersionId = newAlternativeVersionId;
 	}

src/vs/editor/common/services/modelServiceImpl.ts

@@ -140,6 +140,7 @@ class DisposedModelInfo {
 	constructor(
 		public readonly uri: URI,
 		public readonly sha1: string,
+		public readonly versionId: number,
 		public readonly alternativeVersionId: number,
 	) { }
 }
@@ -346,6 +347,7 @@ export class ModelServiceImpl extends Disposable implements IModelService {
 					element.setModel(model);
 				}
 				this._undoRedoService.setElementsIsValid(resource, true);
+				model._overwriteVersionId(disposedModelData.versionId);
 				model._overwriteAlternativeVersionId(disposedModelData.alternativeVersionId);
 			} else {
 				this._undoRedoService.removeElements(resource);
@@ -481,7 +483,7 @@ export class ModelServiceImpl extends Disposable implements IModelService {
 		if (maintainUndoRedoStack) {
 			// We only invalidate the elements, but they remain in the undo-redo service.
 			this._undoRedoService.setElementsIsValid(resource, false);
-			this._disposedModels.set(MODEL_ID(resource), new DisposedModelInfo(resource, computeModelSha1(model), model.getAlternativeVersionId()));
+			this._disposedModels.set(MODEL_ID(resource), new DisposedModelInfo(resource, computeModelSha1(model), model.getVersionId(), model.getAlternativeVersionId()));
 		} else {
 			this._undoRedoService.removeElements(resource);
 		}

src/vs/editor/test/common/services/modelService.test.ts

@@ -327,6 +327,25 @@ suite('ModelService', () => {
 			model2.undo();
 			assert.equal(model2.getValue(), 'text');
 		});
+
+		test('maintains version id and alternative version id for same resource and same content', () => {
+			const resource = URI.parse('file://test.txt');
+
+			// create a model
+			const model1 = modelService.createModel('text', null, resource);
+			// make an edit
+			model1.pushEditOperations(null, [{ range: new Range(1, 5, 1, 5), text: '1' }], () => [new Selection(1, 5, 1, 5)]);
+			assert.equal(model1.getValue(), 'text1');
+			const versionId = model1.getVersionId();
+			const alternativeVersionId = model1.getAlternativeVersionId();
+			// dispose it
+			modelService.destroyModel(resource);
+
+			// create a new model with the same content
+			const model2 = modelService.createModel('text1', null, resource);
+			assert.equal(model2.getVersionId(), versionId);
+			assert.equal(model2.getAlternativeVersionId(), alternativeVersionId);
+		});
 	}
 
 	test('does not maintain undo for same resource and different content', () => {